Agua Caliente Band of Cahuilla Indians v. Coachella Valley Water District , 849 F.3d 1262 ( 2017 )


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  •                 FOR PUBLICATION
    UNITED STATES COURT OF APPEALS
    FOR THE NINTH CIRCUIT
    AGUA CALIENTE BAND OF CAHUILLA          No. 15-55896
    INDIANS,
    Plaintiff-Appellee,        D.C. No.
    5:13-cv-00883-
    UNITED STATES OF AMERICA,                  JGB-SP
    Intervenor-Plaintiff-Appellee,
    v.                       OPINION
    COACHELLA VALLEY WATER
    DISTRICT; ED PACK, in Official
    Capacity as Member of the Board of
    Directors of the Coachella Valley
    Water District; JOHN POWELL, JR., in
    Official Capacity as Member of the
    Board of Directors of the Coachella
    Valley Water District; PETER
    NELSON, in Official Capacity as
    Member of the Board of Directors of
    the Coachella Valley Water District;
    G. PATRICK O’DOWD, in Official
    Capacity as a Member of the Board
    of Directors of the Coachella Valley
    Water District; CASTULO R.
    ESTRADA, in Official Capacity as a
    Member of the Board of Directors of
    the Coachella Valley Water District;
    DESERT WATER AGENCY; PATRICIA
    G. OYGAR, in Official Capacity as
    Member of the Board of Directors of
    2                AGUA CALIENTE BAND V.
    COACHELLA VALLEY WATER DIST.
    the Desert Water Agency; THOMAS
    KIELEY, III, in Official Capacity as
    Member of the Board of Directors of
    the Desert Water Agency; JAMES
    CIOFFI, in Official Capacity as
    Member of the Board of Directors of
    the Desert Water Agency; CRAIG A.
    EWING, in Official Capacity as
    Member of the Board of Directors of
    the Desert Water Agency; JOSEPH K.
    STUART, in Official Capacity as
    Member of the Board of Directors of
    the Desert Water Agency,
    Defendants-Appellants.
    Appeal from the United States District Court
    For the Central District of California
    Jesus G. Bernal, District Judge, Presiding
    Argued and Submitted October 18, 2016
    Pasadena, California
    Filed March 7, 2017
    Before: Richard C. Tallman and Morgan B. Christen,
    Circuit Judges, and Matthew F. Kennelly, * District Judge.
    Opinion by Judge Tallman
    *
    The Honorable Matthew F. Kennelly, United States District Judge
    for the Northern District of Illinois, sitting by designation.
    AGUA CALIENTE BAND V.                               3
    COACHELLA VALLEY WATER DIST.
    SUMMARY **
    Water Rights / Tribal Rights
    The panel affirmed the district court’s partial summary
    judgment in favor of the Agua Caliente Band of Cahuilla
    Indians and the United States, which declared that the United
    States impliedly reserved appurtenant water sources,
    including groundwater, when it created the Tribe’s
    reservation in California’s arid Coachella Valley.
    The Tribe filed this action for declaratory and injunctive
    relief against water agencies, and the parties stipulated to
    divide the litigation into three phases. Phase I, at issue in this
    interlocutory appeal, addressed whether the Tribe has a
    reserved right to groundwater.
    Under the doctrine in Winters v. United States, 
    207 U.S. 564
     (1908), federal reserved water rights are directly
    applicable to Indian reservations.
    The panel held that the Winters doctrine does not
    distinguish between surface water and groundwater. The
    panel held that the United States, in establishing the Agua
    Caliente reservation, impliedly reserved water. The panel
    further held that because the United States intended to
    reserve water when it established a home for the Agua
    Caliente Band of Cahuilla Indians, the district court did not
    err in determining that the government reserved appurtenant
    water sources – including groundwater – when it created the
    **
    This summary constitutes no part of the opinion of the court. It
    has been prepared by court staff for the convenience of the reader.
    4               AGUA CALIENTE BAND V.
    COACHELLA VALLEY WATER DIST.
    Tribe’s reservation in the Coachella Valley. The panel also
    held that the creation of the Agua Caliente Reservation
    carried with it an implied right to use water from the
    Coachella Valley aquifer.
    The panel rejected the water agencies’ arguments
    concerning the contours of the Tribe’s reserved water rights.
    The panel held that state water rights are preempted by
    federal reserved rights. The panel also held that the fact that
    the Tribe did not historically access groundwater did not
    destroy its right to groundwater now. Finally, the panel held
    that the Tribe’s entitlement to state water did not affect the
    analysis with respect to the creation of the Tribe’s federally
    reserved water right.
    COUNSEL
    Steven Bane Abbott (argued), Gerald D. Shoaf, and Julianna
    K. Tillquist, Redwine and Sherrill, Riverside, California, for
    Defendants-Appellants Coachella Valley Water District, G.
    Patrick O’Dowd, Ed Pack, John Powell Jr., Peter Nelson,
    and Castulo R. Estrada.
    Roderick E. Walston (argued), Arthur L. Littleworth,
    Michael T. Riddell, and Steven G. Martin, Best Best &
    Krieger LLP, Walnut Creek, California, for Defendants-
    Appellants Desert Water Agency, Patricia G. Oygar,
    Thomas Kieley III, James Cioffi, Craig A. Ewing, and
    Joseph K. Stuart.
    Catherine F. Munson (argued), Kilpatrick Townsend &
    Stockton LLP, Washington, D.C.; Steven C. Moore and
    Heather Whiteman Runs Him, Native American Rights
    AGUA CALIENTE BAND V.                        5
    COACHELLA VALLEY WATER DIST.
    Fund, Boulder, Colorado; Mark H. Reeves, Kilpatrick
    Townsend & Stockton LLP, Augusta, Georgia; Adam H.
    Charnes, Kilpatrick Townsend & Stockton LLP, Dallas,
    Texas; for Plaintiff-Appellee.
    Elizabeth A. Peterson (argued), Yosef M. Negose, Daron T.
    Carreiro, Patrick Barry, John L. Smeltzer, and William B.
    Lazarus, Attorneys; John C. Cruden, Assistant Attorney
    General; United States Department of Justice, Washington,
    D.C.; Christopher Watson and Scott Bergstrom, Office of
    the Solicitor, United States Department of the Interior,
    Washington, D.C.; for Intervenor-Plaintiff-Appellee.
    OPINION
    TALLMAN, Circuit Judge:
    “When the well’s dry, we know the worth of
    water.” Benjamin Franklin (1706–1790),
    Poor Richard’s Almanac.
    The Coachella Valley Water District (“CVWD”) and the
    Desert Water Agency (“DWA”) (collectively, the “water
    agencies”) bring an interlocutory appeal of the district
    court’s grant of partial summary judgment in favor of the
    Agua Caliente Band of Cahuilla Indians (the “Tribe”) and
    the United States. The judgment declares that the United
    States impliedly reserved appurtenant water sources,
    including groundwater, when it created the Tribe’s
    reservation in California’s arid Coachella Valley. We agree.
    In affirming, we recognize that there is no controlling federal
    appellate authority addressing whether the reserved rights
    doctrine applies to groundwater. However, because we
    6              AGUA CALIENTE BAND V.
    COACHELLA VALLEY WATER DIST.
    conclude that it does, we hold that the Tribe has a reserved
    right to groundwater underlying its reservation as a result of
    the purpose for which the reservation was established.
    I
    A
    The Agua Caliente Band of Cahuilla Indians has lived in
    the Coachella Valley since before California entered
    statehood in 1850. The bulk of the Agua Caliente
    Reservation was formally established by two Presidential
    Executive Orders issued in 1876 and 1877, and the United
    States, pursuant to statute, now holds the remaining lands of
    the reservation in trust for the Tribe. The reservation
    consists of approximately 31,396 acres interspersed in a
    checkerboard pattern amidst several cities within Riverside
    County, including Palm Springs, Cathedral City, and
    Rancho Mirage. See Agua Caliente Band of Mission Indians
    v. Riverside County, 
    442 F.2d 1184
    , 1185 (9th Cir. 1971).
    The Executive Orders establishing the reservation are
    short in length, but broad in purpose. In 1876, President
    Ulysses S. Grant ordered certain lands “withdrawn from sale
    and set apart as reservations for the permanent use and
    occupancy of the Mission Indians in southern California.”
    Exec. Order of May 15, 1876. Similarly, President
    Rutherford B. Hayes’s 1877 Order set aside additional lands
    for “Indian purposes.” Exec. Order of Sept. 29, 1877. These
    orders followed on the heels of detailed government reports
    from Indian agents, which identified the urgent need to
    reserve land for Indian use in an attempt to encourage tribal
    members to “build comfortable houses, improve their acres,
    and surround themselves with home comforts.” Comm’r of
    Indian Aff., Ann. Rep. 224 (1875). In short, the United
    AGUA CALIENTE BAND V.                                 7
    COACHELLA VALLEY WATER DIST.
    States sought to protect the Tribe and “secure the Mission
    Indians permanent homes, with land and water enough.”
    Comm’r of Indian Aff., Ann. Rep. 37 (1877).
    Establishing a sustainable home in the Coachella Valley
    is no easy feat, however, as water in this arid southwestern
    desert is scarce. Rainfall totals average three to six inches
    per year, and the Whitewater River System—the valley’s
    only real source of surface water—produces an average
    annual supply of water that fluctuates between 4,000 and
    9,000 acre-feet, most of which occurs in the winter months. 1
    See CVWD, Engineer’s Report on Water Supply and
    Replenishment Assessment at III-12 (2016–2017); CVWD,
    Urban Water Management Plan at 3-2, 3-20 (2005). In other
    words, surface water is virtually nonexistent in the valley for
    the majority of the year. Therefore, almost all of the water
    1
    An acre-foot is the volume of water sufficient to cover one acre in
    area at a depth of one foot. CVWD, 2010–2011 Annual Review at 2. It
    is equivalent to 325,851 gallons. 
    Id.
     It takes about four acre-feet of
    water to irrigate one acre of land for a year in the Coachella Valley. See
    U.S. Dep’t of Agric., A Review of Agricultural Water Use in the
    Coachella Valley at 6 (2006). Therefore, at 9,000 acre-feet per year, the
    river system provides enough water to irrigate around 2,250 acres. At
    4,000 acre-feet per year, the system can only irrigate about 1,000 acres.
    Considering that the Tribe is not the only user of the Whitewater River
    System, and that its reservation alone accounts for 31,396 acres, even in
    a peak year the river system provides very little water for irrigation or
    for human consumption.
    8                AGUA CALIENTE BAND V.
    COACHELLA VALLEY WATER DIST.
    consumed in the region comes from the aquifer underlying
    the valley—the Coachella Valley Groundwater Basin. 2
    The Coachella Valley Groundwater Basin supports 9
    cities, 400,000 people, and 66,000 acres of farmland. See
    CVWD-DWA, The State of the Coachella Valley Aquifer at
    2. Given the demands on the basin’s supply, it is not
    surprising that water levels in the aquifer have been
    declining at a steady rate. Since the 1980s, the aquifer has
    been in a state of overdraft, 3 which exists despite major
    efforts to recharge the basin with water delivered from the
    California Water Project and the Colorado River. In total,
    groundwater pumping has resulted in an average annual
    recharge deficit of 239,000 acre-feet, with cumulative
    overdraft estimated at 5.5 million acre-feet as of 2010.
    The Tribe does not currently pump groundwater on its
    reservation.    Rather, it purchases groundwater from
    Appellant water agencies. The Tribe also receives surface
    water from the Whitewater River System, particularly the
    Andreas and Tahquitz Creeks that sometimes flow nearby.
    The surface water received from this system is consistent
    with a 1938 California Superior Court adjudication—the
    Whitewater River Decree—which attempted to address
    state-law water rights for users of the river system. Because
    the United States held the lands in trust, it participated in the
    2
    The CVWD estimates that surface water accounts for less than five
    percent of its water supply each year. See CVWD, Urban Water
    Management Plan at 3-20 (2005).
    3
    Overdraft occurs when the amount of water extracted from the
    underground basin exceeds its recharge rate. CVWD, 2010–2011
    Annual Review at 2.
    AGUA CALIENTE BAND V.                                   9
    COACHELLA VALLEY WATER DIST.
    adjudication via a “Suggestion” on behalf of the Tribe and
    the resulting state court order included a water allotment for
    the Tribe’s benefit. 4 The amount of water reserved for the
    Tribe from this adjudication, however, is minimal, providing
    enough water to irrigate approximately 360 acres. Further,
    most of this allotment is filled outside of the growing season
    because the river system’s flow peaks between December
    and March. Thus, groundwater supplied by the water
    agencies remains the main source of water for all types of
    consumption on the reservation throughout the year.
    B
    Given an ever-growing concern over diminishing
    groundwater resources, the Agua Caliente Tribe filed this
    action for declaratory and injunctive relief against the water
    agencies in May 2013. The Tribe’s complaint requested a
    declaration that it has a federally reserved right and an
    aboriginal right to the groundwater underlying the
    reservation. In June 2014, the district court granted the
    United States’ motion to intervene as a plaintiff. The United
    States also alleges that the Tribe has a reserved right to
    groundwater.
    The parties stipulated to divide the litigation into three
    phases. Phase I, at issue here, seeks to address whether the
    Tribe has a reserved right and an aboriginal right to
    groundwater. According to the parties’ stipulation, Phase II
    4
    In providing this “Suggestion,” the government maintained that it
    was not “submitting the rights of the United States . . . to the jurisdiction
    of the Department of Public Works of the State of California” and that
    the court lacked “jurisdiction [to adjudicate] the water rights of the
    United States.” The federal government continues to maintain this
    position before us.
    10                AGUA CALIENTE BAND V.
    COACHELLA VALLEY WATER DIST.
    will address whether the Tribe beneficially owns the “pore
    space” of the groundwater basin underlying the Agua
    Caliente Reservation and whether a tribal right to
    groundwater includes the right to receive water of a certain
    quality. Finally, Phase III will attempt to quantify any
    identified groundwater rights.
    In March 2015, the district court granted in part and
    denied in part Plaintiffs’ and Defendants’ cross motions for
    partial summary judgment with respect to Phase I of the
    litigation. In its order, the district court held that the reserved
    rights doctrine applies to groundwater and that the United
    States reserved appurtenant groundwater when it established
    the Tribe’s reservation. 5 The district court then certified its
    order for interlocutory appeal pursuant to 
    28 U.S.C. § 1292
    (b), and we granted the water agencies’ petition for
    permission to prosecute this appeal.
    II
    The district court’s grant of summary judgment is
    reviewed de novo. Tohono O’odham Nation v. City of
    Glendale, 
    804 F.3d 1292
    , 1297 (9th Cir. 2015); Lopez v.
    Smith, 
    203 F.3d 1122
    , 1131 (9th Cir. 2000) (en banc).
    Summary judgment is appropriate when there is no genuine
    issue as to any material fact and the moving party is entitled
    to judgment as a matter of law. Fed. R. Civ. P. 56(a);
    Anderson v. Liberty Lobby, Inc., 
    477 U.S. 242
    , 247–48
    5
    The district court also held that the Tribe does not have an
    aboriginal right to the groundwater. An aboriginal right is a type of
    property right that derives from territorial occupancy of land. See United
    States ex rel. Chunie v. Ringrose, 
    788 F.2d 638
    , 641–42 (9th Cir. 1986).
    However, the Tribe did not appeal this issue, and we do not review it
    here.
    AGUA CALIENTE BAND V.                       11
    COACHELLA VALLEY WATER DIST.
    (1986). A court shall grant summary judgment when, “under
    the governing law, there can be but one reasonable
    conclusion as to the verdict.” Anderson, 477 U.S. at 250.
    III
    Due to the unusual trifurcation of this litigation, we are
    concerned on appeal only with Phase I—whether the Tribe
    has a federal reserved right to the groundwater underlying its
    reservation. This question, however, is best analyzed in
    three steps: whether the United States intended to reserve
    water when it created the Tribe’s reservation; whether the
    reserved rights doctrine encompasses groundwater; and,
    finally, whether the Tribe’s correlative rights under state law
    or the historic lack of drilling for groundwater on the
    reservation, or the water the Tribe receives pursuant to the
    Whitewater River Decree, impacts our answers to these
    questions. We address each in turn.
    A
    For over one hundred years, the Supreme Court has made
    clear that when the United States “withdraws its land from
    the public domain and reserves it for a federal purpose, the
    Government, by implication, reserves appurtenant water
    then unappropriated to the extent needed to accomplish the
    purpose of the reservation.” Cappaert v. United States,
    
    426 U.S. 128
    , 138 (1976) (citing U.S. Const. art. I, § 8; U.S.
    Const. art. IV, § 3); see also Winters v. United States,
    
    207 U.S. 564
    , 575–78 (1908); Colville Confederated Tribes
    v. Walton, 
    647 F.2d 42
    , 46 (9th Cir. 1981).
    In what has become known as the Winters doctrine,
    federal reserved water rights are directly applicable “to
    Indian reservations and other federal enclaves,
    12              AGUA CALIENTE BAND V.
    COACHELLA VALLEY WATER DIST.
    encompassing water rights in navigable and nonnavigable
    streams.” See Cappaert, 
    426 U.S. at 138
    . The creation of
    these rights stems from the belief that the United States,
    when establishing reservations, “intended to deal fairly with
    the Indians by reserving for them the waters without which
    their lands would have been useless.” Arizona v. California,
    
    373 U.S. 546
    , 600 (1963); see also 
    id.
     at 598–99 (“It is
    impossible to believe that when Congress created the great
    Colorado River Indian Reservation and when the Executive
    Department of this Nation created the other reservations they
    were unaware that most of the lands were of the desert
    kind—hot, scorching sands—and that water from the river
    would be essential to the life of the Indian people and to the
    animals they hunted and the crops they raised.”).
    Despite the longstanding recognition that Indian
    reservations, as well as other reserved lands, require access
    to water, the Winters doctrine only applies in certain
    situations: it only reserves water to the extent it is necessary
    to accomplish the purpose of the reservation, and it only
    reserves water if it is appurtenant to the withdrawn land.
    Winters, 
    207 U.S. at
    575–78; Cappaert, 
    426 U.S. at 138
    .
    Once established, however, Winters rights “vest[] on the date
    of the reservation and [are] superior to the rights of future
    appropriators.” Cappaert, 
    426 U.S. at 138
    .
    B
    1
    Given the limitations in the Winters doctrine, we must
    first decide whether the United States, in establishing the
    Agua Caliente Reservation, impliedly reserved water. See
    United States v. New Mexico, 
    438 U.S. 696
    , 701 (1978). We
    conclude that it did. And although the parties and the district
    AGUA CALIENTE BAND V.                              13
    COACHELLA VALLEY WATER DIST.
    court focused on the application of the Winters doctrine to
    groundwater specifically, their argument over the creation of
    a federal reserved right—and, in particular, the relevance of
    New Mexico to that question—depends on whether the Agua
    Caliente Reservation carried with it a reserved right to water
    generally. Whether the Tribe’s reserved right extends to the
    groundwater underlying its reservation is a separate question
    from whether the establishment of the reservation contained
    an implicit right to use water.
    In New Mexico, the Supreme Court emphasized that,
    under the reserved rights doctrine, the government reserves
    only “that amount of water necessary to fulfill the purpose
    of the reservation, no more.” 
    Id.
     (quoting Cappaert,
    
    426 U.S. at 141
    ). “Where water is only valuable for a
    secondary use of the reservation, . . . the United States
    [must] acquire water in the same manner as any other public
    or private appropriator.” Id. at 702. In other words, New
    Mexico established a “primary-secondary use” distinction.
    Water is impliedly reserved for primary purposes. It is not,
    however, reserved for secondary purposes. 6
    The water agencies argue that New Mexico requires us—
    when deciding if a reserved right exists at all—to determine
    whether water is necessary to fulfill the primary purpose of
    the Agua Caliente Reservation. If it is not, they argue, then
    we are to conclude that Congress did not intend any water to
    be impliedly reserved under a federal water right. Put
    6
    We have previously noted that New Mexico is “not directly
    applicable to Winters doctrine rights on Indian reservations.” United
    States v. Adair, 
    723 F.3d 1394
    , 1408 (9th Cir. 1983). However, it clearly
    “establish[es] several useful guidelines.” 
    Id.
     Thus, we consider its
    application here.
    14             AGUA CALIENTE BAND V.
    COACHELLA VALLEY WATER DIST.
    differently, the water agencies argue that New Mexico stands
    for the proposition that water is impliedly reserved only if
    other sources of water then available cannot meet the
    reservation’s water demands. According to the water
    agencies, if other sources of water exist—and the lack of a
    federal right would not entirely defeat the purpose of the
    reservation—then Congress intended to defer to state water
    law and require the United States to obtain water rights like
    any other private user.
    New Mexico, however, is not so narrow. Congress does
    not defer to state water law with respect to reserved rights.
    
    Id. at 702, 715
    . Instead, Congress retains “its authority to
    reserve unappropriated water . . . for use on appurtenant
    lands withdrawn from the public domain for specific federal
    purposes.” 
    Id. at 698
    .
    The federal purpose for which land was reserved is the
    driving force behind the reserved rights doctrine. “Each time
    [the] Court has applied the ‘implied-reservation-of-water-
    doctrine,’ it has carefully examined both the asserted water
    right and the specific purposes for which the land was
    reserved, and concluded that without the water the purposes
    of the reservation would be entirely defeated.” 
    Id. at 700
    .
    But the question is not whether water stemming from a
    federal right is necessary at some selected point in time to
    maintain the reservation; the question is whether the purpose
    underlying the reservation envisions water use.
    Winters itself established that the purpose of the
    reservation is controlling. In Winters, the Supreme Court
    addressed whether the federal government reserved water
    for tribal usage at the Fort Belknap Indian Reservation,
    which had been reserved by the United States “as and for a
    permanent home” for several tribes. 
    207 U.S. at 565
    . The
    AGUA CALIENTE BAND V.                        15
    COACHELLA VALLEY WATER DIST.
    Winters Court observed that the arid tribal reservation would
    be “practically valueless,” and that a civilized community
    “could not be established thereon,” without irrigation. 
    Id. at 576
    . Thus, the Court held that, in creating the reservation,
    the United States simultaneously reserved water “for a use
    which would be necessarily continued through years.” 
    Id. at 577
    . The reserved right turned on the purpose underlying
    the formation of the Fort Belknap Reservation.
    Though it was decided seventy years after Winters, New
    Mexico remains faithful to this construction. In analyzing
    the reserved rights doctrine, the Court first sought to
    determine Congress’ intent in creating the Gila National
    Forest. New Mexico, 
    438 U.S. at 698
    . After reviewing the
    congressional act that established the forest, the Court
    determined that Congress intended only two purposes—“to
    conserve the water flows, and to furnish a continuous supply
    of timber for the people.” 
    Id. at 707
     (citation omitted). It
    did not, however, reserve the forest lands for aesthetic,
    environmental, recreational, or wildlife-preservation
    purposes. 
    Id. at 708
    . Thus, the Court deemed the latter uses
    “secondary,” for which the reserved right did not attach, and
    held that only “to fulfill the very purposes for which a federal
    reservation was created . . . [did] the United States intend[]
    to reserve the necessary water.” 
    Id. at 702
    .
    As such, New Mexico’s primary-secondary use
    distinction did not alter the test envisioned by Winters.
    Rather, it added an important inquiry related to the question
    of how much water is reserved. It also answered that
    question by holding that water is reserved only for primary
    purposes, those directly associated with the reservation of
    land. It did not, however, eliminate the threshold issue—that
    16               AGUA CALIENTE BAND V.
    COACHELLA VALLEY WATER DIST.
    a reserved right exists if the purposes underlying a
    reservation envision access to water.
    2
    Because New Mexico holds that water is reserved if the
    primary purpose of the reservation envisions water use, we
    now determine the primary purpose of the Tribe’s
    reservation and whether that purpose contemplates water
    use. To do so, we consider “the document and circumstances
    surrounding [the reservation’s] creation, and the history of
    the Indians for whom it was created.” Walton, 
    647 F.2d at 47
    .
    The Executive Orders establishing the Tribe’s
    reservation declared that the land was to be set aside for “the
    permanent use and occupancy of the Mission Indians” or,
    more generally, for “Indian purposes.” 7 See supra Part I.
    While imprecise, such a purpose is not indecipherable. Our
    precedent recognizes that “[t]he specific purposes of an
    Indian reservation . . . [are] often unarticulated. The
    general purpose, to provide a home for the Indians, is a broad
    one and must be liberally construed.” Walton, 
    647 F.2d at 47
     (emphasis added). Moreover, “[m]ost of the land in these
    reservations is and always has been arid,” and it is
    impossible to believe that the United States was unaware
    “that water . . . would be essential to the life of the Indian
    people.” Arizona, 
    373 U.S. at
    598–99.
    7
    Additionally, government reports preceding the Executive Orders
    recognized the need to secure the Tribe “permanent homes, with land
    and water enough.” See Comm’r of Indian Aff., Ann. Rep. 37 (1877).
    AGUA CALIENTE BAND V.                              17
    COACHELLA VALLEY WATER DIST.
    The situation facing the Agua Caliente Tribe is no
    different. Water is inherently tied to the Tribe’s ability to
    live permanently on the reservation. Without water, the
    underlying purpose—to establish a home and support an
    agrarian society—would be entirely defeated.              Put
    differently, the primary purpose underlying the
    establishment of the reservation was to create a home for the
    Tribe, and water was necessarily implicated in that purpose.
    Thus, we hold that the United States implicitly reserved a
    right to water when it created the Agua Caliente Reservation.
    C
    While we conclude that the federal government
    envisioned water use when it established the Tribe’s
    reservation, that does not end our inquiry. We must now
    determine whether the Winters doctrine, and the Tribe’s
    reserved water right, extends to the groundwater underlying
    the reservation. And while we are unable to find controlling
    federal appellate authority explicitly holding that the Winters
    doctrine applies to groundwater, 8 we now expressly hold
    that it does.
    Apart from the requirement that the primary purpose of
    the reservation must intend water use, the other main
    limitation of the reserved rights doctrine is that the
    8
    We previously held that the Winters doctrine applies “not only [to]
    surface water, but also to underground water.” United States v.
    Cappaert, 
    508 F.2d 313
    , 317 (9th Cir. 1974), aff’d on other grounds,
    Cappaert, 
    426 U.S. at 142
    . But on appeal, the Supreme Court did not
    reach this question. See Cappaert, 
    426 U.S. at 142
    . In that case, the
    peculiarities of the hydrological forms led the Court to conclude as a
    question of fact that the reserved water in a cavern pool was surface
    water, not groundwater. 
    Id.
    18                AGUA CALIENTE BAND V.
    COACHELLA VALLEY WATER DIST.
    unappropriated water must be “appurtenant” to the
    reservation. See Cappaert, 
    426 U.S. at 138
    . Appurtenance,
    however, simply limits the reserved right to those waters
    which are attached to the reservation. It does not limit the
    right to surface water only. Cappaert itself hinted that
    impliedly reserved waters may include appurtenant
    groundwater when it held that “the United States can protect
    its water from subsequent diversion, whether the diversion
    is of surface or groundwater.” 
    Id. at 143
    . If the United States
    can protect against groundwater diversions, it follows that
    the government can protect the groundwater itself. 9
    Further, many locations throughout the western United
    States rely on groundwater as their only viable water source.
    See, e.g., In re Gen. Adjudication of All Rights to Use Water
    in Gila River Sys. & Source, 
    989 P.2d 739
    , 746 (Ariz. 1999)
    (en banc) (“The reservations considered in [Winters and
    Arizona] depended for their water on perennial streams. But
    some reservations lack perennial streams and depend for
    present and future survival substantially or entirely upon
    pumping of underground water. We find it no more
    thinkable in the latter circumstance than in the former that
    9
    Although the district court found that the groundwater contained
    in the Coachella Valley aquifer “does not ‘add to, contribute to or
    support’ any surface stream from which the Tribe diverts water,” that
    does not mean that the hydrological cycle in the Coachella Valley has
    been severed. See U.S. Geological Surv., Ground Water and Surface
    Water: A Single Resource, U.S.G.S. Circular 1139 at 9–10 (1998)
    (recognizing a connection between surface and groundwater even where
    the water table falls below the stream bed). Further, we note that surface
    water is used here to replenish groundwater sources. As such, the district
    court may wish to hear expert opinion on the interconnectedness of the
    waters in the valley in the later phases of this litigation. Proper factual
    findings on this issue will allow the district court to fashion appropriate
    relief during the quantification phase.
    AGUA CALIENTE BAND V.                           19
    COACHELLA VALLEY WATER DIST.
    the United States reserved land for habitation without
    reserving the water necessary to sustain life.”). More
    importantly, such reliance exists here, as surface water in the
    Coachella Valley is minimal or entirely lacking for most of
    the year. Thus, survival is conditioned on access to water—
    and a reservation without an adequate source of surface
    water must be able to access groundwater.
    The Winters doctrine was developed in part to provide
    sustainable land for Indian tribes whose reservations were
    established in the arid parts of the country. And in many
    cases, those reservations lacked access to, or were unable to
    effectively capture, a regular supply of surface water. Given
    these realities, we can discern no reason to cabin the Winters
    doctrine to appurtenant surface water. As such, we hold that
    the Winters doctrine encompasses both surface water and
    groundwater appurtenant to reserved land. 10 The creation of
    the Agua Caliente Reservation therefore carried with it an
    implied right to use water from the Coachella Valley aquifer.
    D
    The final issue we must address is the contours of the
    Tribe’s reserved right, including its relation to state water
    law and the Tribe’s existing water rights.
    A “reserved right in unappropriated water . . . vests on
    the date of the reservation and is superior to the rights of
    future appropriators.” Cappaert, 
    426 U.S. at 138
    . Further,
    reserved rights are not analyzed “in terms of a balancing
    10
    The parties do not dispute appurtenance, nor could they. The
    Coachella Valley Groundwater Basin clearly underlies the Tribe’s
    reservation. See generally CVWD, Engineer’s Report on Water Supply
    and Replenishment Assessment (2016–2017).
    20              AGUA CALIENTE BAND V.
    COACHELLA VALLEY WATER DIST.
    test.” 
    Id.
     Rather, they are federal water rights that preempt
    conflicting state law. See Walton, 
    647 F.2d at
    51–53; see
    also New Mexico, 
    438 U.S. at 715
     (“[T]he ‘reserved rights
    doctrine’ . . . is an exception to Congress’ explicit deference
    to state water law in other areas.”). Finally, the rights are not
    lost through non-use. See Walton, 
    647 F.2d at 51
    . Instead,
    they are flexible and can change over time. See 
    id.
     at 47–48;
    United States v. Ahtanum Irrigation Dist., 
    236 F.2d 321
    , 326
    (9th Cir. 1956).
    Despite the federal primacy of reserved water rights, the
    water agencies argue that because (1) the Tribe has a
    correlative right to groundwater under California law and
    (2) the Tribe has not drilled for groundwater on its
    reservation, and (3) because the Tribe is entitled to surface
    water from the Whitewater River Decree, the Tribe does not
    need a federal reserved right to prevent the purpose of the
    reservation from being entirely defeated. Put differently, the
    water agencies argue that, because the Tribe is already
    receiving water pursuant to California’s correlative rights
    doctrine and the Whitewater River Decree, a federal
    reserved right is unnecessary.
    However, the water agencies’ arguments fail for three
    reasons. First, state water rights are preempted by federal
    reserved rights. See Walton, 
    647 F.2d at 51
    ; see also
    Ahtanum Irrigation Dist., 
    236 F.2d at 329
     (“Rights reserved
    by treaties such as this are not subject to appropriation under
    state law, nor has the state power to dispose of them.”).
    Second, the fact that the Tribe did not historically access
    groundwater does not destroy its right to groundwater now.
    See Walton, 
    647 F.2d at 51
    . And third, the New Mexico
    inquiry does not ask if water is currently needed to sustain
    the reservation; it asks whether water was envisioned as
    AGUA CALIENTE BAND V.                        21
    COACHELLA VALLEY WATER DIST.
    necessary for the reservation’s purpose at the time the
    reservation was created. See supra Part III.B. Thus, state
    water entitlements do not affect our analysis with respect to
    the creation of the Tribe’s federally reserved water right.
    IV
    In sum, the Winters doctrine does not distinguish
    between surface water and groundwater. Rather, its limits
    derive only from the government’s intent in withdrawing
    land for a public purpose and the location of the water in
    relation to the reservation created. As such, because the
    United States intended to reserve water when it established
    a home for the Agua Caliente Band of Cahuilla Indians, we
    hold that the district court did not err in determining that the
    government reserved appurtenant water sources—including
    groundwater—when it created the Tribe’s reservation in the
    Coachella Valley.
    Finally, we recognize that the district court’s failure to
    conduct a thorough New Mexico analysis with respect to
    whether the Tribe needs access to groundwater was largely
    a function of the parties’ decision to trifurcate this case. We
    also understand that a full analysis specifying the scope of
    the water reserved under New Mexico will be considered in
    the subsequent phases of this litigation.
    Presumably, however, the water agencies will continue
    to argue in these later phases that the Winters doctrine is
    dependent upon the Tribe’s demonstrated need—that is,
    need above and beyond what the Tribe is already receiving
    under state-law entitlements or could receive through a
    paramount surface water right. And while we express no
    opinion on how much water falls within the scope of the
    Tribe’s federal groundwater right, there can be no question
    22              AGUA CALIENTE BAND V.
    COACHELLA VALLEY WATER DIST.
    that water in some amount was necessarily reserved to
    support the reservation created. Thus, to guide the district
    court in its later analysis, we hold that the creation of the
    Agua Caliente Reservation carried with it an implied right to
    use water from the Coachella Valley aquifer.
    Each party shall bear its own costs.
    AFFIRMED.